Secession (noun)

1. The withdrawal of a group from a larger organization, especially a political entity, a trade union, or a religious organization.
2. The action or an act of secreting oneself away.

Origin:

Early 19th century: from latin secessio(n-) "withdrawal", from secedere "go away".

Examples:

1. The state's secession from the Union was a major cause of the Civil War.
2. The group's secession from the organization was a surprise to everyone.
3. The company's secession from the trade association was a sign of the growing divide.
4. The country's secession from the European Union caused a lot of controversy.
5. The secession of the group caused a schism in the organization.